Synthesis and in vitro evaluation of 5-substituted benzovesamicol analogs containing N-substituted amides as potential positron emission tomography tracers for the vesicular acetylcholine transporter.
Bioorg Med Chem
; 25(19): 5095-5106, 2017 10 01.
Article
em En
| MEDLINE
| ID: mdl-28185725
ABSTRACT
Herein, new ligands for the vesicular acetylcholine transporter (VAChT), based on a benzovesamicol scaffold, are presented. VAChT is acknowledged as a marker for cholinergic neurons and a positron emission tomography tracer for VAChT could serve as a tool for quantitative analysis of cholinergic neuronal density. With an easily accessible triflate precursor, aminocarbonylations were utilized to evaluate the chemical space around the C5 position on the tetrahydronaphthol ring. Synthesized ligands were evaluated for their affinity and selectivity for VAChT. Small, preferably aromatic, N-substituents proved to be more potent than larger substituents. Of the fifteen compounds synthesized, benzyl derivatives (±)-7i and (±)-7l had the highest affinities for VAChT. Compound (±)-7i was chosen to investigate the importance of stereochemistry for binding to VAChT and selectivity toward the σ1 and σ2 receptors. Enantiomeric resolution gave (+)-7i and (-)-7i, and the eutomer showed seven times better affinity. Although racemate (±)-7i was initially promising, the affinity of (-)-7i for VAChT was not better than 56.7nM which precludes further preclinical evaluation. However, the nanomolar binding together with the ready synthesis of [11C]-(±)-7i shows that (-)-7i can serve as a scaffold for future optimizations to provide improved 11C-labelled VAChT PET tracers.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Piperidinas
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Radioisótopos de Carbono
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Tomografia por Emissão de Pósitrons
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Proteínas Vesiculares de Transporte de Acetilcolina
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Amidas
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article